Fast Idle

[SAM. C.]

Hi Gents

I have just got my Pertronix working thanks to Jim & Scott. It is running well and starts real easy but after it has been driven for a while the idle is much too fast. I find that if I rev it once the idle will go back to normal but it will not drop back itself.

It may have nothing to do with the Pertronix as it was running so S**t that I wouldnt have noticed it before.

Does anyone have any ideas?

Cheers

Sam

[Profpinz]

Sam, I'd check the carburettor return springs first off, but an initial "work through" of the ignition system, timing, and basic carburettor setup may show that a whole lot of little things are the problem rather than one thing!

[SAM. C.]

Hi Peter

Thanks for the reply.

I have had a quick look today at the mechanical linkage as I suspected it might be that but it seems to be ok, it snaps back and is not sticky at all. I have only just set the timing and it runs fine except for the idle, pick up seems fine would the timing affect the return to idle?

With regard to the carbs I have a bit to learn. When you say basic setup what are you thinking?

Cheers

Sam

[hrafn]

Sam,

I had the same problem and I eventually found that the advance mechanism
in the distributor was gummed up. You will need to take the distributor apart
to give it a good cleaning and a coat of light oil. It is also possible that the
return springs on the weights are weak and need replacing.

Jim LaGuardia has a nice photo collection of a distributor rebuild here:
http://www.goatwerks.com/distributorgallery.htm

It is not a difficult job to rebuild the distributor.

[krick3tt]

Thanks for the tips. My idle is fine after start up but gets higher when driving. If I stop at a light it goes up to 1200+ and a brief tug on the throttle handle will usually bring it down. I have gotten used to it.
At least now, after going through the linkage and carbs, I have another place to look for gremlins.
When it warms up a bit (weather) I will get into it.

Cheers,
Morris

[gunnar]

Does anyone know where to get new springs for the Dizzy or are they included in the Bosh Kit: 1237010007
I could also need new weights..

Cheers,
Gunnar

[SAM. C.]

Hi All

Peter was right it was the return springs. It looked like it was retuning all of the way when the engine was not running but I was driving yesterday with the dog house off and I pushed the throttle lever down and it moved another couple of MM or so. Just enough to bring the idle back down to normal. I will try and find a stronger spring or cannibalise the one I have to make it a bit stronger.

Thanks for the replies and a happy festive season to all.

Sam

[todds112]

Hi All

Peter was right it was the return springs. It looked like it was retuning all of the way when the engine was not running but I was driving yesterday with the dog house off and I pushed the throttle lever down and it moved another couple of MM or so. Just enough to bring the idle back down to normal. I will try and find a stronger spring or cannibalise the one I have to make it a bit stronger.

Thanks for the replies and a happy festive season to all.

Sam

Gotta love it when it's something so simple (and inexpensive ).

I am amazed at how many Aussies are flooding into town for the ski season. Sure hope we start getting some snow.

[krick3tt]

I have noticed that with colder temps (ambient air) the idle goes up even farther. I am guessing that the oil or grease on the internals of the dizzy gets thicker and with the gunk already there, and it does not return all the way. Even goosing the gas does not help anymore.
Guess there is no getting around this one, waiting for it to get better is not the path to take.
I will have to check out the dizzy tear down photos by Jim.

Morris

[pinzinator]

I've brought this up before, because I had a 710M with the same problem. Everything appeared OK, including the throttle return. Eventually I discovered that the carbs were not syncronized, something you cannot easily detect without the proper equipment and mechanic. One butterfly has to open very slightly to make this scenario. My advice is to see a mechanic who is familiar with multiple carbs and can do the work without guessing. An exhaust gas analyzer is essential. My 2 cents.